Open a new drawing in DataCAD, then pick the Insert (pulldown menu) / Sketchup then a window opens allowing you to change to the directory where you have the SKP file(s). Select the SKP file and then insert it into the drawing. SKP files import their 3D faces/polygons though material colours may need editing to what you want.I don't use Sketchup so can't answer how importing works into it. .... you might find it just as quick to continue modelling in DataCAD so everything is in the one program? (use 3D solids, covered polylines or smart entities or a combination).